PHP学习练手（十一）

给脚本传值

1、方法一：利用HTML的隐藏输入框类型

<input type="hidden" name="do" value="this" />

在提交form表单时，$_POST[‘do’]将具有this这个值（假定表单使用POST方式）

2、把值追加到URL上

www.example.com/page.php?do=this

这种方式模仿了html表单的GET方法。

3、view_user3.php——该脚本能够展示Edit和Delete链接，并在每个url中传递一起传递用户的ID号

<?php #Script 9.4 -view_users.php

$page_title = 'View the Current Users';
include ('../include/header.html');

echo '<h1>Registered Users</h1>';

require ('../mysqli_connect.php');

$sql = "SELECT last_name, first_name, DATE_FORMAT(registration_date, '%M %d, %Y') AS dr, user_id FROM users ORDER BY registration_date ASC";

$res = @mysqli_query ($mysqli, $sql);

$nums = mysqli_num_rows($res);
if($nums > 0)
{
echo "<p>There are currently $nums registered users</p>";

echo '<table align="center" cellspacing="3" width="75%">
<tr>
<td align="left"><b>Edit</b></td>
<td align="left"><b>Delete</b></td>
<td align="left"><b>Last</b></td>
<td align="left"><b>First</b></td>
<td align="left"><b>Date Registered</b></td>
</tr>';
while ($rows = mysqli_fetch_array($res, MYSQLI_ASSOC)) {
echo '<tr>
<td align="left"><a href="edit_user.php?id='.$rows['user_id'].'">Edit</a></td>
<td align="left"><a href="delete_user.php?id='.$rows['user_id'].'">Delete</a></td>
<td align="left">'.$rows['last_name'].'</td>
<td align="left">'.$rows['first_name'].'</td>
<td align="left">'.$rows['dr'].'</td>
</tr>';
}
echo '</table>';
mysqli_free_result($res);  //释放掉资源

}//if_$nums
else{
echo '<p class="error">The current users could not be retrieved. We apologize for any inconvenience.</p>';

echo '<p>'.mysqli_error($mysqli).'<br/ ><br/ >Query: '.$sql.'</p>';
}

mysqli_close($mysqli);

include ('../include/footer.html');

?>

运行后：



知识点：

为了把多个变量追加到URL中，可以使用下面这种语法：page.php?name1=value?&name2=value2&name3=value3…

添加变量到url中的一种技巧是应该对字符串编码。以确保值会被正确处理。解决方案是使用urlencode()函数：

$url = ‘page.php?’.urlencode(‘Elli Simth’);

单提交表单时，GET方式会自动正确的执行。

4、delete_user.php——使用隐藏的表单输入框

<?php # Script 10.2 - delete_user.php
$page_title = 'Delete a User';
include ('../include/header.html');
echo '<h1>Delete a User</h1>';

if((isset($_GET['id'])) && (is_numeric($_GET['id'])))
{
$id = $_GET['id'];
}elseif((isset($_POST['id'])) && (is_numeric($_POST['id'])))
{
$id = $_POST['id'];
}else{
echo '<p class="error">This page has been accessed in error.</p>';
exit();
}

require_once('../mysqli_connect.php');

if($_SERVER['REQUEST_METHOD'] == 'POST')
{
if($_POST['sure'] == 'Yes')
{
$sql = "DELETE FROM users WHERE user_id=$id LIMIT 1";
$res = @mysqli_query($mysqli, $sql);
if(mysqli_affected_rows($mysqli) == 1)
{
echo '<p>The user has been deleted</p>';
}else{
echo '<p class="error">The user could not be deleted due to a system.</p>';
echo '<p>'.mysqli_error($mysqli).'<br/ >Query:'.$sql.'</p>';
}
}else{
echo '<p>The user has NOT been deleted.</p>';
}
}else{
$sql = "SELECT CONCAT(last_name, ',', first_name) FROM users WHERE user_id = $id";
$res = @mysqli_query($mysqli, $sql);

if(mysqli_num_rows($res) == 1)
{
$row = mysqli_fetch_array($res, MYSQLI_NUM);

echo "<h3>Name: $row[0]</h3>
Are you sure you want to delete this user?";

echo '<form action="delete_user.php" method="post">
<input type="radio" name="sure" value="Yes"/>Yes
<input type="radio" name="sure" value="No" checked="checked"/>No
<input type="submit" name="submit" value="Submit"/>
<input type="hidden" name="id" value="'.$id.'"/>
</form>';
}else{
echo '<p class="error">This page has been accessed in error.</p>';
}
}

mysqli_close($mysqli);

include('../include/footer.html');

?>

当从如下图所示页面进入delete_user.php，会出现：





原因如下：

if((isset($_GET['id'])) && (is_numeric($_GET['id'])))
{
$id = $_GET['id'];
}elseif((isset($_POST['id'])) && (is_numeric($_POST['id'])))
{
$id = $_POST['id'];
}else{
echo '<p class="error">This page has been accessed in error.</p>';
exit();
}

由于这种进入方式并没有提交表单，故直接进入到报错的echo中。。。

当从view_users3.php进入时，如下：



选择No，提交：



选择Yes，提交：



5、edit_user.php

<?php
$page_title = 'Edit a User';
include ('../include/header.html');
echo '<h1>Edit a User</h1>';

if((isset($_GET['id'])) && (is_numeric($_GET['id'])))
{
$id = $_GET['id'];
}elseif((isset($_POST['id'])) && (is_numeric($_POST['id'])))
{
$id = $_POST['id'];
}else{
echo '<p class="error">This page has been accessed in error.</p>';
exit();
}

require_once('../mysqli_connect.php');

if($_SERVER['REQUEST_METHOD'] == 'POST')
{
$errors = array();

//检查first name
if(empty($_POST['first_name']))
{
$errors[] = 'You forgot to enter your first name';
}else{
$fn = mysqli_real_escape_string($mysqli, trim($_POST['first_name']));
}

//检查last name
if (empty($_POST['last_name']))
{
$errors[] = 'You forgot to enter your last name';
}else{
$ln = mysqli_real_escape_string($mysqli, trim($_POST['last_name']));
}

//检查email Address
if (empty($_POST['email']))
{
$errors[] = 'You forgot to enter your email';
}else{
$e = mysqli_real_escape_string($mysqli, trim($_POST['email']));
}

if(empty($errors))
{
$sql = "SELECT user_id FROM users WHERE email= '$e' AND user_id != '$id'"; //判断提交的电子邮件地址是否尚未使用
$res = @mysqli_query($mysqli, $sql);
if(mysqli_num_rows($res) == 0)
{//若表中不存在该邮件使用者的ID,表明邮件尚未使用
$sql = "UPDATE users SET first_name= '$fn', last_name= '$ln', email= '$e' WHERE user_id= $id LIMIT 1";
$res = @mysqli_query($mysqli, $sql);
if(mysqli_affected_rows($mysqli) == 1) //受影响记录条数
{
echo '<p>The user has been edited.</p>';
}else{
echo '<p>The user could not be edited due to a system error. We apologize for any inconvenience</p>';
echo '<p>'.mysqli_error($mysqli).'<br /><br />'.$sql.'</p>';
}

}else{
echo '<p>The email address has been already been registered.</p>';
}
}//if_$errors
else{
echo '<h1>Error!</h1>
<p class="error">The following error(s) occured:<br/ >';
foreach ($errors as $msg) {
echo "- $msg<br/ >";
}
echo '</p><p>Please try again</p><p><br/ ></p>';
}

}

$sql = "SELECT first_name, last_name, email FROM users WHERE user_id = $id";
$res= @mysqli_query($mysqli, $sql);

if(mysqli_num_rows($res) == 1) //有效的用户ID
{
$rows = mysqli_fetch_array($res, MYSQLI_NUM);

echo '<form action="edit_user.php" method="post">
<p>First Name: <input type="text" name="first_name" size="15" maxlength="15" value="'.$rows[0].'"/></p>
<p>Last Name: <input type="text" name="last_name" size="15" maxlength="30" value="'.$rows[1].'"/></p>
<p>Email Address: <input type="text" name="email" size="20" maxlength="60" value="'.$rows[2].'"/></p>
<input type="submit" name="submit" value="Submit"/>
<input type="hidden" name="id" value="'.$id.'"/>
</form>';
}else{
echo '<p class="error">This page has been accessed in error.</p>';
}

mysqli_close($mysqli);

include('../include/footer.html');

?>

从view_user3.php进入：



修改后提交：

给查询结果标页码

1、view_users4.php

<?php #Script 10.4 -view_users.php

$page_title = 'View the Current Users';
include('../include/header.html');
echo '<h1>Registered Users</h1>';

require_once('../mysqli_connect.php');

$display = 10;

if(isset($_GET['p']) && is_numeric($_GET['p']))
{
$page = $_GET['p'];
}else{
$sql = "SELECT COUNT(user_id) FROM users"; //计算ID数目
$res = @mysqli_query($mysqli, $sql);
$row = @mysqli_fetch_array($res, MYSQLI_NUM);
$records = $row[0];        //获取当前ID数目

//当前ID数目多余每页显示的条数
if($records > $display)
{
//取不小于$records / $display的最小整数

$page = ceil($records / $display);
}else{
$page = 1;
}

}

//调取数据的起始位置
if(isset($_GET['s']) && is_numeric($_GET['s']))
{
$start = $_GET['s'];
}else{
$start = 0;
}

$sql = "SELECT last_name, first_name, DATE_FORMAT(registration_date, '%M %d, %Y') AS dr, user_id FROM users ORDER BY registration_date ASC LIMIT $start, $display";
$res = @mysqli_query($mysqli, $sql);
echo '<table border="1" cellspacing="0" cellpadding="10" align="center">
<tr>
<td align="left"><b>Edit</b></td>
<td align="left"><b>Delete</b></td>
<td align="left"><b>Last Name</b></td>
<td align="left"><b>First Name</b></td>
<td align="left"><b>Date Registered</b></td>
</tr>
';

$bg = '#eee';

while($rows = mysqli_fetch_array($res, MYSQLI_ASSOC))
{
$bg = ($bg == '#eee' ? '#fff' : '#eee');
echo '<tr bgcolor="'.$bg.'">
<td align = "letf"><a href="edit_user.php?id='.$rows['user_id'].'">Edit</a></td>
<td align = "letf"><a href="delete_user.php?id='.$rows['user_id'].'">Delete</a></td>
<td align="left">'.$rows['last_name'].'</td>
<td align="left">'.$rows['first_name'].'</td>
<td align="left">'.$rows['dr'].'</td>
</tr>';
}

echo '</table>';

mysqli_free_result($res);
mysqli_close($mysqli);

if($page > 1)
{
echo '<br/><p>';
$current_page = ($start / $display) + 1;   //当前该显示的页数
if($current_page != 1) //当前显示页大于1
{
echo '<a href="view_users4.php?s='.($start - $display).'&p='.$page.'">Previous </a>';
}

for($i = 1; $i <= $page; $i++)
{
if($i != $current_page)
{
echo '<a href="view_users4.php?s='.(($display*($i-1))).'&p='.$page.'">'.$i.' </a>';
}else{
echo $i.' ';
}
}

if($current_page != $page)
{
echo '<a href="view_users4.php?s='.($start+$display).'&p='.$page.'"> Next</a>';
}
echo '</p>';
}//if_$page>1

include ('../include/footer.html');

?>

代码解析：

if($records > $display)
{
//取不小于$records / $display的最小整数

$page = ceil($records / $display);
}else{
$page = 1;
}

——上述$page表示当前数据中的数据一共可以显示成多少个页面。

if($current_page != 1) //当前显示页大于1
{
echo '<a href="view_users4.php?s='.($start - $display).'&p='.$page.'">Previous </a>';
}

——如果当前页面不是第一个页面（即页码>1），它还需要一个Previous连接，指向早期的结果集。前一页的起点将是当前起点减去要显示的数量。

for($i = 1; $i <= $page; $i++)
{
if($i != $current_page)
{
echo '<a href="view_users4.php?s='.(($display*($i-1))).'&p='.$page.'">'.$i.' </a>';
}else{
echo $i.' ';
}
}

——通过1到页面的总数的循环来创建一批连接，除了当前页面外，其余的页面均会被链接

if($current_page != $page)
{
echo '<a href="view_users4.php?s='.($start+$display).'&p='.$page.'"> Next</a>';
}

——如果当前页面不是最终页面，则存在一个Next链接到下页面。

运行后如下：

建立可排序的显示结果

1、view_users5.php

<?php #Script 10.4 -view_users.php

$page_title = 'View the Current Users';
include('../include/header.html');
echo '<h1>Registered Users</h1>';

require_once('../mysqli_connect.php');

$display = 10;

if(isset($_GET['p']) && is_numeric($_GET['p']))
{
$page = $_GET['p'];
}else{
$sql = "SELECT COUNT(user_id) FROM users"; //计算ID数目
$res = @mysqli_query($mysqli, $sql);
$row = @mysqli_fetch_array($res, MYSQLI_NUM);
$records = $row[0];        //获取当前ID数目

//当前ID数目多余每页显示的条数
if($records > $display)
{
//取不小于$records / $display的最小整数

$page = ceil($records / $display);
}else{
$page = 1;
}

}

//调取数据的起始位置
if(isset($_GET['s']) && is_numeric($_GET['s']))
{
$start = $_GET['s'];
}else{
$start = 0;
}

//设置查询顺序
$sort = (isset($_GET['sort'])) ? $_GET['sort'] : 'rd';

switch($sort)
{
case 'ln':
$order_by = 'last_name ASC';
break;
case 'fn':
$order_by = 'first_name DESC';
break;
case 'rd':
$order_by = 'registration_date DESC';
break;
default:
$order_by = 'registration_date ASC';
$sort = 'rd';
break;
}

$sql = "SELECT last_name, first_name, DATE_FORMAT(registration_date, '%M %d, %Y') AS dr, user_id FROM users ORDER BY $order_by LIMIT $start, $display";

/*$sql = "SELECT last_name, first_name, DATE_FORMAT(registration_date, '%M %d, %Y') AS dr, user_id FROM users ORDER BY registration_date ASC LIMIT $start, $display";*/
$res = @mysqli_query($mysqli, $sql);

echo '<table border="1" cellspacing="0" cellpadding="10" align="center">
<tr>
<td align="left"><b>Edit</b></td>
<td align="left"><b>Delete</b></td>
<td align="left"><b><a href="view_users5.php?sort=rn">Last Name</a></b></td>
<td align="left"><b><a href="view_users5.php?sort=fn">First Name</a></b></td>
<td align="left"><b><a href="view_users5.php?sort=rd">Date Registered</a></b></td>
</tr>
';

$bg = '#eee';

while($rows = mysqli_fetch_array($res, MYSQLI_ASSOC))
{
$bg = ($bg == '#eee' ? '#fff' : '#eee');
echo '<tr bgcolor="'.$bg.'">
<td align = "letf"><a href="edit_user.php?id='.$rows['user_id'].'">Edit</a></td>
<td align = "letf"><a href="delete_user.php?id='.$rows['user_id'].'">Delete</a></td>
<td align="left">'.$rows['last_name'].'</td>
<td align="left">'.$rows['first_name'].'</td>
<td align="left">'.$rows['dr'].'</td>
</tr>';
}

echo '</table>';

mysqli_free_result($res);
mysqli_close($mysqli);

if($page > 1)
{
echo '<br/><p>';
$current_page = ($start / $display) + 1;   //当前该显示的页数
if($current_page != 1) //当前显示页大于1
{
/*echo '<a href="view_users4.php?s='.($start - $display).'&p='.$page.'&">Previous </a>';*/
echo '<a href="view_users5.php?s='.($start - $display).'&p='.$page.'&sort='.$sort.'">Previous </a>';
}

for($i = 1; $i <= $page; $i++)
{
if($i != $current_page)
{
echo '<a href="view_users5.php?s='.(($display*($i-1))).'&p='.$page.'&sort='.$sort.'">'.$i.' </a>';
}else{
echo $i.' ';
}
}

if($current_page != $page)
{
echo '<a href="view_users5.php?s='.($start+$display).'&p='.$page.'&sort='.$sort.'"> Next</a>';
}
echo '</p>';
}//if_$page>1

include ('../include/footer.html');

?>

<td align="left"><b><a href="view_users5.php?sort=rn">Last Name</a></b></td>
<td align="left"><b><a href="view_users5.php?sort=fn">First Name</a></b></td>
<td align="left"><b><a href="view_users5.php?sort=rd">Date Registered</a></b></td>

——给标题添加排序链接，点击First Name运行如下：